a. Field of the Invention
The present invention relates to the field of storm shelters. More particularly, the present invention relates to in-ground shelters which either can be installed in new construction or can be retrofit, for example, in a garage in an existing structure.
b. Description of the Prior Art
The idea of a shelter from dangerous forces such as tornados, hurricanes or bombs has been around for decades. See, for example, Pierson, U.S. Pat. No. 3,114,153 for a Combination Shelter and Swimming Pool. While less than optimally functional (what, for example, does one do about the water in the pool if one needs to use the shelter?), Pierson illustrates that the idea of an in-ground shelter is not new. Presumably, Pierson was focusing his efforts as a shelter that might protect a user from the threat of Soviet nuclear attack. Before Pierson, many people installed simple cellars primarily for food storage, but also for protection from storms. Entrance to these early shelters was usually accomplished by a hinged door.
More relevant to the present invention are Hope et al., U.S. Pat. No. 6,161,345, and Poole, U.S. Pat. No. 5,953,866. Hope et al., claimed a “tornado shelter,” and Poole claimed a “storm shelter.” Both are for a shelter which is designed to be installed below ground, and which has a sliding substantially flat access door near ground level to allow ingress and egress. The door in Poole, which is the patent closest to the present invention, appears to covers approximately one-third of the top of the shelter. The door sits on rollers, and rolls downwardly and inwardly to open. That is, it rolls down underneath of the rest of the shelter's top.
Poole claims a similar device, but the description in Poole and the drawings are much more limited. There is no description in Poole about how the lid, as shown open in FIG. 6, is prevented from tipping over as it is opened. The force of gravity would, as shown in FIGS. 5 and 6 of Poole, force the leading edge of the lid to tip under its own weight. There is no structure shown or described in Poole which would prevent this from happening. Further, the Poole lid is well above ground level, which may prevent a vehicle from parking above the shelter if installed in a garage and which would also present a tripping hazard.
Ueno et al., U.S. Pat. No. 5,732,512 shows a manhole opening structure. While it is not directly related to the present art, it does allow access to an under-ground cavity, and it does have a substantially flat lid which opens to allow access. The problem with Ueno is that the lid slides on the ground. As the lid slides, it may slide over an uneven ground surface surrounding it, and the sliding would be less than uniform, especially given the debris that might gather around the shelter as a result of the storm. It would be very difficult to open a device such as one described by Ueno in a storm shelter context. Therefore, while Ueno is instructive, it does not show or describe the features of the claimed invention.
The inventor in the present matter, Jerry Wirtz, was also an inventor on Vaughn et al., U.S. Pat. No. 7,428,800. That application discloses and claims a storm shelter having substantially, the entire top of the box defining an opening, the lid adapted to be substantially flush with the surrounding ground level in a closed position, and roller means with a track affixed to each of the side walls near the open top and parallel thereto at least one upper track roller disposed between the lid and each track, each upper track roller supporting the lid as it moves relative to the track, a support means for supporting a leading edge of the lid as it slides over the surrounding ground level, the support means having at least one rail roller adjacent to the back wall disposed between the lid and the track, a lower track roller attached to the lid ncar the trailing edge, the lower track roller engaging a lower track surface, at least one rail affixed to the underside of the lid between the rail roller and the lid, each rail having a sloped section near the leading edge of the lid, whereby when the leading edge moves away from the back wall, the lid is displaced upwardly by operation of the sloped section against the rail roller, providing additional clearance for the lid as it passes over the ground surface.